Catalytic alkylation of aromatics with paraffins



United States Patent 3 109,038 CATALYTIC ALKYlLATIUN 9F ARGldATECS WITHPARAFFHNS John W. Myers, Bartlesville, Okla, assignor to PhillipsPetroleum Company, a corporation of Delaware No Drawing. Filed Sept. 6,1960, Ser. No. 53,900 9 Claims. (Cl. 260-671) This invention relates tothe production of alkyl aromatic compounds. In one aspect, the inventionrelates to the formation of alkyl derivatives from aromatichydrocarbons. In another aspect, the invention relates to the formationfrom aromatic hydrocarbons of derivatives containing one or more alkylgroups more than are contained in the original aromatic hydrocarbon. Inanother aspect, this invention relates to a method of producingalkylated aromatic compounds from aromatic compounds and parafiins. Inanother aspect, the invention relates to the utilization of an improvedcatalytic process for reacting paratfins and aromatics. In a stillfurther aspect, the invention relates to the alkylation of an aromatichydrocarbon with an aliphatic hydrocarbon in the presence of a catalystof at least one of platinum, rhodium, palladium, iridium, nickel, andcobalt on an acid support.

It has been known for some time how to prepare alkylated aromatichydrocarbons wherein an alkyl group is attached to the aromatic moleculethrough utilization of a catalytic means or condensing agent. These areillustrated by the well known synthesis of Friedel and Crafts, in whichan alkyl halide is caused to alkylate an aromatic molecule by the aid ofaluminum chloride, by the reaction of an olefin and an aromatichydrocarbon in the presence of some condensation agents such asphosphoric acid or aluminum chloride and by other similar means.

Aromatic hydrocarbons such as benzene, naphthalene, toluene, xylene, andothers are produced in relative abundance in the destructivedistillation of coal, in the enrichment of manufactured gas by thecracking of petroleum, and in gas reforming pyrolysis. However, onlyrelatively small amounts of aikylated derivatives such as ethylmnzene,propylbenzene, alkyl naphthalenes, are formed in these operations. Thealkylated derivatives of the aromatics differ from the purely cyclicaromatics in properties and are valuable in a variety of special uses.

I have found that alkylation of aromatic compounds with paraifins isgreatly improved when carried out in the presence of a catalyst of atleast one of platinum, rhodium, palladium, iridium, nickel, and cobalton an acid support.

Therefore, it is an object of this invention to provide an improvedprocess for the alkylation of aromatics with parafiins. A further objectof this invention is to provide an improved method for effecting theformation of alkyl derivatives from aromatic hydrocarbons in thepresence of a catalyst of platinum, rhodium, palladium, iridium, nickel,and cobalt on an acid support. Another object of this invention is theformation of alkyl derivatives from aromatic hydrocarbons with a higheryield of alkyl aromatics.

Other aspects, objects, and the several advantages of the invention areapparent from a study of the disclosure and the appended claims.

According to this invention, there is provided an improved catalyticprocess for reacting paraffins and aromatics. In this process, parafiinssuch as ethane, propane, butane, and the like, and aromatics such asbenzene, toluene, xylene, and the like, are contacted with an acidiccatalyst containing a promoter having dehydrogenation activity, atelevated temperatures and preferably at elevated pressures. The processis carried out by passing a mixed paraffin-aromatic feed over thecatalyst at temperatures usually in the range of about 400 F. to 900 F,preferably in the range of about 550 F. to 850 F., at pressures usuallyin the range from about 0 to 5,000 p.s.i. g. or even higher, preferablyin the range from about 250 to 3,000 p.s.i.g., wd liquid hourly spacevelocities usually in the range from about 0.1 to 10, preferably in therange from about 0.1 to 5.

The catalyst is at least one of platinum, rhodium, palladium, iridium,nickel, and cobalt supported on an acidic support such as halogenatedalumina, silica-alumina, boria-alumina, or zinc chloride-alumina.Suitable catalysts are platinum-halogen-alumina,platinum-silica-alumina, platinum-boria-alumina, and platinum-zincchloride-alumina, and the corresponding composites of rhodium, iridium,palladium, cobalt, and nickel. The catalyst will usually contain in therange of about 0.01 to 10 weight percent, preferably in the range ofabout 0.1 to 2 weight percent of the metal, the remainder being thesupport. These catalysts can be made by any known process, such asimpregnation. The supports should have surface areas of at least about25 square meters per gram, preferably at least about square meters pergram. The impregnation of the support can be effected by using anaqueous salt solution of the metallic component, and the impregnatedsupport dried and then reduced at elevated temperatures to decompose thesalt and form the metallic component.

A preferred catalyst composition is platinum or palladium on halogenatedalumina. The metallic component is ordinarily in the range of about 0.01to 10 Weight percent, preferably in the range of about 0.1 to 2 weightpercent. The halogen is ordinarily in the range of about 0.5 to 10weight percent, preferably in the range of about 1 to 7 weight percent.The remainder is substantially alumina. Chlorine and fluorine aresuitable for use as the halogen component. This type of catalyst is wellknown in the art as are methods of production.

The feed to the process consists essentially of at least one aromatic tobe alkylated and at least one parafiin alkylating agent. The aromaticcan be benzene, naphthalene, an incompletely alkylated benzene ornaphthalene, and the like. Mixtures of these aromatics can also be used.The alkylating agent can be either straightor branched-chain and canhave 2 to about 10 carbon atoms. Mixtures of these parafiins can also beused. The feed should have a mol ratio of paraffin to aromatic of atleast about 0.221 to 10:1, preferably at least about 0.5 :1 to 521. Asthe paraffin is relatively non-reactive in condensing with itself, highmol ratios of alkylatable hydrocarbon to alkylating agent are of lessimportance in this process than in the more conventional processes usingmore reactive alkylating agents.

When using a platinum family metal on halogenated alumina as thecatalyst, it is desirable to include a small amount of hydrogen halide,alkyl halide or alkylene halide in the feed as an activator. Amounts inthe range of about 0.05 to 0.5 weight percent, based on the hydrogenhalide available on decomposition are satisfactory. Chlorides arepreferred as activators.

Example A mixture of 35.7 weight percent propane, 64.0 weight 3 Ipercent benzene, and 0.3 Weight percent ethylene dichloride wascontacted with a catalyst of 0.37 weight percent platinum, 3.4- percentfluorine, less than 0.05 percent chlorine and the remainder alumina. Theprocess was operated continuously at 900 p.s.i.g., 694 F, and 0.6 LHSV.

The efi'luent contained 6.6 Weight percent of components boiling abovebenzene. The analysis of the higher boiling material was WeightComponent Percent Toluene 3 n-Propylbcnzene 22 i-Propylbenzene 45Heavier 30 It is evident that the predominant products werepropylbenzenes, and the amount was close to the estimated thermodynamicequilibrium.

Reasonable variation and modification are possible within the scope ofthe foregoing disclosure and the appended claims to the invention, theessence of which is an improved process for the catalytic alkylation ofaromatics with paramns in the presence of .a catalyst of at least one ofplatinum, rhodium, iridium, palladium, nickel, and cobalt on an acidsupport.

I claim:

1. A method for adding an alkyl group to an aromatic hydrocarbon whichcomprises subjecting a feed consisting essentially of at least onearomatic to be alkylated and at least one paraffin selected from thegroup consisting of ethane, propane, and butane to a reactingtemperature in the range of about 400 F. to about 900 F., at a pressurein the range of about 0 to about 5,000 p.s.i.g., at a liquid hourlyspace velocity in the range of about 0.1 to about 10, and in thepresence of a catalyst of at least one element selected from the groupconsisting of palladium, platinum, rhodium, iridium, nickel and cobalton an acid support, to form alkyl substituted derivatives, andseparating from the process the alkyl substituted derivatives soproduced.

2. A method in accordance with claim 1 wherein said catalyst is aplatinum-halogen-alumina catalyst.

3. A method in accordance with claim 1 wherein said reaction temperatureis in the range of about 550 F. to about 850 F., said pressure is in therange of about 250 to about 3000 p.s.i.g. and said liquid hourly spacevelocity is in the range of about 0.1 to about 5.

4. A method in accordance with claim 1 further comprising adding to saidfeed a small amount of an element selected from the group consisting ofhydrogen halide, alkyl halide, and an alkylene halide as an activator.

5. A method in accordance with claim 1 wherein said aromatic is benzeneand said catalyst is a platinum-fluorine-alumina catalyst.

6. A method in accordance with claim 1 wherein said catalyst comprisessaid element in the range of about 0.01 to about 10 Weight percent, ahalogen in the range of about 0.5 to about 10 weight percent, andalumina.

7. A method in accordance with claim 6 wherein said element is in therange of about 0.01 to about 2 weight percent and said halogen is in therange of about 1 to about 7 Weight percent.

8. A method in accordance with claim 1 wherein the A References Cited inthe file of this patent UNITED STATES PATENTS Cox June 16, 19532,752,289 Haensel June 26, 1956 2,777,805 Lefrancois et al. Jan. 15,1957 OTHER REFERENCES Sachanen, Chemical Constituents of Petroleum,1945, published by Reinhold Publishing Co. (New York), page 214 reliedupon.

1. A METHOD FOR ADDING AN ALKYL GROUP TO AN AROMATIC HYDROCARBON WHICHCOMPRISES SUBJECTING A FEED CONSISTING ESSENTIALLY OF AT LEAST ONEAROMATIC TO BE ALKYLATED AND AT LEAST ONE PARAFFIN SELECTED FROM THEGROUP CONSISTING OF ETHANE, PROPANE, AND BUTANE TO A REACTINGTEMPERATURE IN THE RANGE OF ABOUT 400* F. TO ABOUT 900* F., AT APRESSURE IN THE RANGE OF ABOUT 0 TO ABOUT 5,000 P.S.I.G., AT A LIQUIDHOURLY SPACE VELOCITY IN THE RANGE OF ABOUT 0.1 TO ABOUT 10, AND IN THEPRESENCE OF A CATALYST OF AT LEAST ONE ELEMENT SELECTED FROM THE GROUPCONSISTING OF PALLADIUM, PLATINUM, RHODIUM, IRIDIUM, NICKEL AND COBALTON AN ACID SUPPORT, TO FORM ALKYL SUBSTITUTED DERIVATIVES, ANDSEPARATING FROM THE PROCESS THE ALKYL SUBSTITUTED DERIVATIVES SOPRODUCED.